This invention relates to a latch, more particularly a latch suitable for latching a window in a closed and sealed position.
Current window fasteners for aluminium awning and casement windows are of a lever handle type which will generally be surface mounted to the interior face of the window sash. These handles have a dual purpose of acting as a handle to pull the window sash closed and also to clamp the window sash to the frame for security and weather sealing.
Weather sealing is achieved by a tongue attached to the lever-handle that acts against a wedge attached to the window frame. Thus, when the lever is rotated the tongue slides along the wedge. This causes the window to be pulled tight against weather strips joined to the aluminium section. The lever is large enough to allow the user to comfortably pull a large window closed and also to generate enough torque to effect the sealing of the window.
Variations of the lever-handle include versions where the wedge is a mechanical device attached to the fastener so that a separate wedge is not required on the window frame. Another variation is a lever that includes two tongues so that a vented position can be achieved. The vented position allows the window to be opened far enough to allow air flow past the window seals to provide semi-secure house venting.
A new type of sliding door system is being developed by a window manufacturer that requires windows to be mounted on the sliding door panel. In this case, the sliding panel slides on the external side of the sliding door system so that any open windows will freely pass a fixed vertical frame member. Clearance between the sliding stile and fixed vertical frame member is thus limited. Consequently any latch furniture associated with the sliding door can only have a maximum protrusion when in the latching position so as to provide sufficient clearance.
It is an object of the present invention to provide a latch for a window wherein the latch has minimal protrusion from the surface of the window.